Well, they are not going to show you the video of another royal grandson who is now a millionaire sun basking somewhere on a beach in Costa Rica. There is no emotive thrill there to tell such a story. This is why in the company of Vietnamese always claim to have less so they look down on you to pity and befriend you. Just let them introduce you to all their pharmacy and dentist friends with calculated glee, "ah here is my friend Quoc, he works at a hotel cleaning bedsheets, but he can speak 6 languages, recite Othello by heart, and make nuoc mam by hand from wild salmon he fished in Alaska."

Nguyen Dynasty is like Noveau Riche. Tell them you´re descended from the last emperor of the Later Ly Dynasty. It has the word "later" in the dynasty name so you bet it´s old! That will show all these Nguyens who´s boss I can´t do it because my surname is Nguyen but just pick a dynasty with your surname and do it.